I own a Corsair TX650 and I've misplaced the powercord after moving locations. I've found a few that could be it so I was wondering if anyone has it and could tell me any thing on the cable that can help me differentiate it.

And in that case that I can't find it at all, what could I do? Do you think corsair will send me a new one for free?

chose the fatter one. also usually the yhave a rating printed on the side there. like 65c, 105c. i have some monster ones from ages past, industrial grade. the wieght on these for the same lenght vs your everyday unit is stupidly immense.

Different cables have different current ratings, so they are not all held to a single standard (aside from the physical interface, of course). As for those mixers, they either weren't really 3000W (the most likely scenario) or they were running off of 220V circuits. PSU cables are typically rated for 10A or 15A, which would allow you to draw up to 1800W from a 120V circuit before the cable overheats.

In this case, it doesn't really matter which cable you use, since even a cheap 10A cable is more than capacious enough to handle the current draw. When dealing with crazy high-end systems however (like kruzn's quad-480 box for example), you have to make sure that you use a cable with a high enough current-carrying capacity or you could end up melting the insulation off the cable or even possibly setting it on fire.